Process for using water-sensitive insecticides as an active ingredient in a water-based pest bait

ABSTRACT

A method of preparing a rapid acting bait composition which is water based and contains a water-sensitive insecticide as an active ingredient is described. The composition is easily applied into cracks and crevices and voids or other pest harborage areas to rapidly kill insect pests, particularly cockroaches. A kit is also described for preparation of the composition.

FIELD OF THE INVENTION

[0001] This invention relates to a water-based, fast-acting pest baitcontaining a water-sensitive insecticide as the active ingredient forcontrolling insects, particularly cockroaches.

BACKGROUND OF THE INVENTION

[0002] Historically, toxic baits for controlling crawling insects suchas cockroaches have been water-based. With cockroaches especially, wateris presumed necessary for good bait performance. Unfortunately,water-based bait products rapidly lose effectiveness due to water loss,rancidity, break-down of active ingredients and other factors. Studiesof water-based paste baits have confirmed that water loss, repellentproperties of active ingredients, and insecticide resistance are themost important factors affecting bait performance. Appel, A. G., J. EconEntomol. 85 (4):1176-1183 (1992), Robinson, W. H., Proceedings of theNational Conference on Urban Entomology 77-91 (1992), and Rust, N. K.,“Managing Household Pests”, in Advances in Urban Pest Management, G. W.Bennett and M. Owens (eds), Van Norstrand Reinhold, N.Y. 335-368 (1986).

[0003] One approach to improve on water-based insecticide products hasbeen to use a dust or a paste composition which includes a so-calledwater powder with the insecticide. This water powder is waterencapsulated with hydrogenated soybean oil. Such a product is describedin U.S. Pat. No. 5,820,855. Unfortunately, dust compositions havedisadvantages such as drifting of the material when applied.

[0004] Water-free fat-based pest bait products are described in U.S.Pat. Nos. 5,464,613 and 5,464,613. These compositions are paste formsand include as a major ingredient a fat-based carrier. Although pasteproducts do not drift, they are difficult to apply and require anapplicator in applying pastes in cracks and crevices or into voids.Another disadvantage of the paste, water-free products are that they arenot as fast-acting as water-based products, especially againstcockroaches.

[0005] Acephate is a very desirable insecticide, particularly in killingcockroaches. Acephate's desirability is based on the fact that there isno known insecticide resistance and because it has a very low mammaliantoxicity. However, acephate is not stable in water-based matrices overtime. Although acephate has been described in the above water-free,fat-based patents, it is not currently used as an active ingredient inany commercially available cockroach bait. There is thus a need forimproved rapid acting, water-based baits that utilize water-sensitiveinsecticides.

SUMMARY OF THE INVENTION

[0006] We have found in the present invention a method which allows awater-sensitive insecticide, for example, acephate, to be usedsuccessfully in a water-based matrix. The invention is a compositionwhich, if desired, can be prepared at the site of application andapplied to cracks, crevices and voids. The composition is active whenformulated and, when applied, results in rapid kill of insect pests,particularly cockroaches. A preferred rapid acting composition is in theform of a gel.

[0007] Accordingly, the invention in its first aspect is a process forpreparing a ready-to-use insecticidal bait composition including thesteps of (a) dissolving a water sensitive insecticide in a specifiedamount of water, (b) combining the resulting insecticidal solution witha bait base containing a mixture of feeding stimulants and optionallycontaining one or more gelling agent(s), (c) agitating the resultingcombination until thoroughly mixed, and, if desired, (d) allowing themixed combination to form a gel or paste.

[0008] The present invention in a second aspect provides a ready-to-useinsecticidal bait composition having a viscosity between about 50,000 toabout 1,500,000 centipoise including (a) about 0.1 to 5.0 wt-% of awater-sensitive insecticide, (b) about 3 to 40 wt-% water, and (c) thebalance being a bait base.

[0009] A third aspect of the present invention is a method ofcontrolling insect pests, particularly cockroaches, by applying to areasto be controlled an effective amount of the above composition.

[0010] Finally, a fourth aspect of the present invention is a kit whichcan be used by the ultimate consumer at the site of application whichcontains the means for the preparation and application of theabove-described composition, optionally in gel form, and includes (a) aclosed impermeable container having a water-sensitive insecticide pelletor powder therein, and (b) a closed packet including a base baitincluding feeding stimulants and, optionally, one or more gellingagent(s). The kit may further include a means for dispensing theready-to-use bait. Otherwise, the mixing packet may be used to apply thecomposition.

BRIEF DESCRIPTION OF THE DRAWING

[0011] The FIGURE is a chart comparing the mean knockdown time onapplying an acephate gel versus a fipronil gel for cockroaches.

DETAILED DESCRIPTION OF THE INVENTION

[0012] The invention involves a water-based insecticidal baitcomposition which includes a water-sensitive insecticide, water and abait base which includes feeding stimulants and, optionally, at leastone or more gelling agents. The composition is preferably a gel and maybe prepared at the site of application by the process described indetail below using a kit, if desired, as described below. Thecomposition of the present invention has the advantages of being rapidlyacting against the insect pests, particularly cockroaches, and can beapplied easily to cracks, crevices and voids or other insect harborageareas.

[0013] Insecticide

[0014] A water-sensitive insecticide is one which is soluble in waterbut is also water degradable. Acephate is a preferred insecticide forthe rapid acting, water-based composition of the present invention.Acephate is a fine crystalline powder that is water soluble. It is adesirable active ingredient because there is no known insecticideresistance and it has very low mammalian toxicity. Acephate has amolecular formula of C₄H₁₀NO₃PS and is chemically known as O,S-dimethylacetylphosphoramidothioate. Typically, acephate and otherwater-sensitive insecticides can be used in the composition at a minimumcontent of about 0.1 wt-%. The preferred range is a concentration ofabout 0.1 to about 5 wt-%. The most preferred amount of acephate in agel composition is about 1 wt-%. Other water-sensitive insecticidesinclude, for example, methamidophos, chemically known as O,S-dimethylphosphoramidothioate, which is the deacetyl analog of acephate.

[0015] Water

[0016] As a water-based composition, water is an essential ingredient ofthe present invention and is used to dissolve the insecticide andsoluble components within the bait base. The amount of water used mayvary depending on the amount of insecticide and the amount of bait base.Thus the amount of water may range from 3 to 40 wt-% of the totalcomposition. Preferably, water is used at about 22-32 wt-%. In apreferred embodiment, 30 wt-% of water is used in a 1.0 wt-% acephatecomposition.

[0017] Bait Base

[0018] The bait base includes a solid mixture of feeding stimulants andattractants which preferably includes at least one gelling agent.Feeding stimulants are included in the composition to attract the insectto the bait, and to entice the insect to eat the bait. Preferable feedstimulants include mixtures of carbohydrates and proteins. Examples ofcarbohydrates are maltodextrins and the like; carbohydrate complexes,corn syrup solids, sugars such as sucrose, glucose, fructose, starchessuch as corn, potato and the like. Examples of proteins include yeastextracts and milk solids, e.g. whole milk powder.

[0019] The feeding stimulants may include, if desired, a gelling agentserving a dual function such as, for example, starches. These starchesare preferably modified, for example, a modified corn starch. Othergelling agents which may be used as part of the bait base include, forexample, gums, e.g. xanthan gum; agars; agaroses; carageenans;bentonite; alginates; collagens; gelatin; polyacrylates; celluloses,cellulose derivatives; polyethylene glycols; polyethylene oxides;polyvinyl alcohols; dextrans; polyacrylamides; polysaccharides, or anyother common gelling agent or viscosity enhancing agent. The preferredgelling agents for the present invention are modified starches.

[0020] In addition to feeding stimulants and gelling agents, the baitbase may also contain additional attractants. Examples of attractantsare odorants and flavorants such as, for example, cyclotenes and thelike, plant extracts such as fenugreek and the like, alcohols such asethanol, or a volatile ester in combination with ethanol. Said volatileester is made from a combination of a C₁-C₆ branched or unbranchedalcohol with C₁-C₃ carboxylic acid. Lower alcohols useful in themanufacture of the volatile ester co-attractants of the inventioninclude methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropylalcohol, n-butyl alcohol, isobutyl alcohol, tertiary butyl alcohol,n-amyl alcohol, isoamyl alcohol, tertiary amyl alcohol, n-hexyl alcohol,and mixtures thereof. Carboxylic acids useful in manufacturing the esterattractant of the invention include acetic acid, propionic acid, butyricacid, mixtures thereof, and others. The associated reactive analogs ofthe respective carboxylic acids can be used, for example, the acidchloride or acid anhydride. The preferred volatile ester for use is alower alcohol acetate ester such as n-amyl acetate, isoamyl acetate,isobutyl acetate, n-propyl acetate, ethyl acetate or mixtures thereof.As with gelling agents and feeding stimulants, some of the ingredientsmay overlap in category as they can be both attractants and feedingstimulants, for example, the proteins mentioned above, odorants andflavorants.

[0021] The bait base may further include as part of the solid mixture upto 50 wt-% (of the total bait base) of borax or boric acid which can beused to lengthen the insecticidal activity of the composition.

[0022] The feeding stimulants, attractants and, optionally, gellingagents are the components of the bait base which contain the balance ofthe composition depending on the amount of insecticide and wateremployed to arrive at the composition. While the bait base containingfeeding stimulants, optional gelling agents and other attractantscontains the balance of the composition, the amount of gelling agent,when used, in this bait base may vary from about 0.1 to 5 wt-% of thetotal solid mixture. The preferred amount of gelling agent is about 1wt-% of the solid bait base mixture.

[0023] Method of Preparation

[0024] The insect pest bait composition is designed to be prepared, ifdesired, at the site of use and may employ a kit which forms part of thepresent invention. The process is best described as follows:

[0025] 1. The active ingredient is contained and stored in its technicalform (95.0%-100% pure) within a glass or otherwise impermeable containerprior to use. The water-sensitive insecticide is preferably contained inthe form of a pellet or powder and the container preferably has aremovable cover and is preferably a glass vial.

[0026] 2. The bait is prepared by combining the insecticide with aspecified amount of water diluent. The solution is agitated until theinsecticide is completely dissolved.

[0027] 3. The finished insecticide solution is then combined with a baitbase which is a solid mixture of feeding stimulants, optional gellingagent and, if desired, other attractants. This mixture is thoroughlyagitated and, if desired, allowed to gel.

[0028] The bait base is preferably contained in a packet, e.g.,typically a resealable plastic bag. When the insecticide solution isadded, the plastic bag is resealed and the contents mixed preferably bythoroughly kneading the materials. The mixed material can be poured intoa dispensing means, e.g. a syringe or dispensing cartridge, oralternatively left in the original mixing packet, until ready for use.Typically, for a 1% acephate composition containing a gelling agent, thegelling time is approximately 20 minutes.

[0029] Depending on the amounts of active ingredient, feed stimulantsand water, the composition may have a viscosity ranging from about50,000 to about 1,500,000 centipoise. Typically, with a 1 wt-% acephategel composition, and using 30% water and bait base as the balance, theviscosity of the resulting gel is about 180,000 centipoise.

[0030] Method of Use

[0031] Once the composition is formed, it can be applied directly ontocracks and crevices for the control of insect pests, particularlycockroaches.

[0032] Application of the composition is useful for food and feedhandling establishments, such as restaurants; dairies; packaging,bottling and canning plants; bakeries; mills or anywhere food and feedis stored, prepared, processed and packaged.

[0033] The composition is also useful in spot and crack and crevicetreatments in food areas. These include, for example, where food or feedis received, stored, prepared, served, packaged, handled in an enclosedsystem and where edible waste is stored. The bait composition may bedirectly applied into cracks and crevices, where equipment meets floorsand walls; equipment and counter legs; bases, motors and conduits; holesand openings leading to wall voids where insects hide.

[0034] The composition may also be used in non-food areas of feed andfood handling establishments including, for example, garbage rooms,restrooms, laboratories, offices, locker rooms, boiler and equipmentrooms, garages, mop closets and storage. The composition also is appliedto cracks and crevices around baseboards, around water and drain pipes,underneath and behind sinks, lockers, tables, and similar areas whereinsects may hide.

[0035] Finally, the composition may be employed in serving areas of foodservice establishments including, for example, dining rooms, mess hallsand other areas where prepared food is served. The composition isapplied in pea-sized or smaller placements onto selected surfaces suchas baseboards, underneath booths and into cracks and crevices.

[0036] The Kit

[0037] Also part of the present invention is a kit which provides thenecessary materials, containers and devices for the ultimate user toprepare the bait composition and apply it to the necessary areasincluding cracks and crevices. The kit is included as a one packageoption for the ultimate user of the bait composition.

[0038] As part of the kit, a container which is impermeable and has acover for closing contains the water-sensitive insecticide in pellet orpowder form. The container is preferably a glass vial.

[0039] The kit also includes a closed packet where the base bait solidmixture is contained. The closed packet is preferably a resealableplastic bag in which the materials are thoroughly mixed and/or kneadedafter adding the insecticide aqueous solution.

[0040] Optionally, the third part of the kit includes a dispensingcontainer which is also closable. The container is preferably acartridge, syringe or cylinder which holds the combination of theaqueous insecticide solution thoroughly mixed with the bait basematerial. The dispensing container can be used for allowing the mixtureto set and form a gel if desired. As an example, the dispensingcartridge is then placed in a bait applicator or connected to a baitapplicator for application of the composition to the cracks andcrevices.

[0041] The entire kit can be obtained as a unitary system assembled in apacket for use at the site.

[0042] The following examples are intended to illustrate the inventionbut are not to be construed in limiting.

EXAMPLES Example 1

[0043] The following acephate composition was prepared:

[0044] 7.0% bakers yeast extract (Universal Flavor Inc. CAS# 8013-01-2)

[0045] 19.0% sucrose (United Sugar Company. CAS# 57-50-01)

[0046] 9.0% ProMax 70L Soy Protein Concentrate (Central Soya, Code4510.)

[0047] 39.0% Calf's Milk Replacer (Cargill, Inc. CAS# N/A)

[0048] 24.0% water

[0049] 1.0% glycerol

[0050] 1.0% acephate (Valent Corp. O, S-dimethylacetylphosphoramidothioate)

[0051] The acephate was dissolved in water, shaken in a coveredcontainer and then added to the mixture of solid ingredients identifiedabove. The ingredients were then allowed to set.

Example 2

[0052] The following test was carried out using the formulation ofExample 1 to measure acephate degradation. The 1.0% acephateformulations of Example 1 were compared for efficacy against cockroachadults and nymphs with the jar/smear method described hereinafter. The4-week aging (ambient) data are reported in the following table as KT50,wherein KT50 is the time in hours to kill 50% of the cockroachpopulation. TABLE Fresh 1 wk 2 wk 4 wk Adult Males: FB#10 0.685 1.0351.157 1.532 Adult Fmls: FB#10 4.780 5.995 1.677 5.082 Lrg Nmphs: FB#101.217 6.325 1.187 4.587 Sm Nmphs: FB#10 0.298 2.134 1.622 4.998

[0053] All biological data indicate that the formulation remainseffective against all life stages for 4.0 weeks after application.

[0054] The jar/smear method is described here:

[0055] Materials

[0056] 1. Bait formulas for screening.

[0057] 2. Mason jars coated on the upper lip with petrolatum to preventescape.

[0058] 3. Balance for measuring bait.

[0059] 4. German cockroaches; 10 per jar.

[0060] 5. Stop watch.

[0061] Method

[0062] 1. Allowed 4 hours for cockroaches to acclimate with food andwater in jars. Allowed alternative food and water to be present duringtesting period.

[0063] 2. Applied 0.3 g of bait to one lip of an inverted plastic weighboat (simulated crack & crevice treatment).

[0064] 3. Following acclimation, ca, 4 hours, placed the baited (andinverted) weigh boat flatly into the jar. Repeated for all cockroachjars in sequence.

[0065] 4. Measured the cockroach mortality over time and determined theKT50 for each cockroach life stage.

Example 3

[0066] The following formulation was prepared with the followingingredients:

[0067] 1.0 wt-% acephate, 30 wt-% water, and 69 wt-% bait base of thefollowing composition: Bait Base Composition Ingredients Supplier Wt %Calf's Milk Replacer Cargill, Inc. 71.31 CAS # N/A Minneapolis,Minnesota 55440 6X powdered sugar United Sugar Company 5.40 CAS #57-50-1 Moorhead, Minnesota 56561 bakers yeast extract Universal FlavorInc. 8.80 CAS # 8013-01-2 Indianapolis, Indiana 46241 food starch -modified National Starch and Chemical 0.94 CAS # 113894-92-1Bridgewarer, New Jersey 08807 sorbitol Archer Daniels Midland 3.70 CAS #50-70-4 Decatur, Illinois 62526 fructose A. E. Staley Manufacturing Co.6.90 CAS # 57-48-7 Decatur, Illinois 62525 sodium chloride Cargill, Inc.1.25 CAS # 7647-14-5 Minneapolis, Minnesota 55440 potassium sorbateArcher Daniels Midland 0.38 CAS # 24634-61-5 Decatur, Illinois 62526citric acid, anhydrous Archer Daniels Midland 1.32 CAS # 77-92-9Decatur, Illinois 62526 Total 100%

[0068] 1. The acephate-storage (vial) was opened and 30 ml of water wasadded to the acephate, 1.04 g). The vial cover was closed and the vialshaken until the acephate was completely dissolved.

[0069] 2. The vial contents were then added to one packet of bait paste(described above), 68.9 g in a zip-lock bag. The packet was closed andthoroughly mixed by shaking and kneading.

[0070] 3. The bait mixture was poured into a dispensing cartridge,covered and allowed to set for 20 minutes for the bait to gel. Theresulting gel had a viscosity of about 180,000 centipoise.

Example 4

[0071] The gel composition of Example 3 was compared with regard to meanknockdown time of cockroaches as effected by the feeding time of thebait composition with a commercially available gel composition whichcontains fipronil as the active ingredient in a concentration of 0.01%.The commercially available fipronil gel composition is used in the samemanner as the composition of the present invention and is claimed to berapid acting. The results of the tests are shown in FIG. 1. The longestmean knockdown time observed for the composition of the presentinvention was 1.62 hours in a 60-second feeding time. In contrast, theshortest fipronil mean knockdown time was 4.42 hours in the same feedingtime, 60 seconds. Notably, in a 5-second feeding time, the gelcomposition of the present invention had a mean knockdown time of 1.18hours whereas the fipronil gel took 20.28 hours for the same five secondfeeding time.

[0072] The above specification, examples and data provide a completedescription of the manufacture and use of the composition of theinvention. Since many embodiments of the invention can be made withoutdeparting from the spirit and scope of the invention, the inventionresides in the claims hereinafter appended.

We claim:
 1. A process for preparing an insecticidal bait composition,the process comprising the following steps: (a) dissolving awater-sensitive insecticide in a specified amount of water; (b)combining the resulting insecticide solution with a bait base comprisinga mixture of feeding stimulants and, optionally, one or more gellingagent(s); (c) agitating the resulting combination until thoroughlymixed; and, if desired, (d) allowing the mixed combination to form a gelor paste.
 2. The process of claim 1 wherein in step (a), water is addedto the water-sensitive insecticide and shaken in a closed impermeablecontainer.
 3. The process of claim 1 wherein in step (b), theinsecticide solution is mixed with the bait base and shaken or kneadedin a closed packet.
 4. The process of claim 3 wherein the mixture ofinsecticide solution and bait base are poured into a dispensingcartridge, covered and allowed to set to form the gel or paste.
 5. Theprocess of claim 1 wherein the composition comprises from about 0.1 toabout 5 wt-% of the insecticide.
 6. The process of claim 1 wherein theinsecticide is acephate or methamidophos.
 7. The process of claim 1wherein the composition comprises about 1 wt-% acephate.
 8. Aninsecticidal bait composition comprising: (a) about 0.1 to 5.0 wt-% of awater soluble, water degradable insecticide; (b) about 3 to 40 wt-%water; and (c) the balance being a bait base; wherein said compositionhas a viscosity between about 50,000 to about 1,500,000 centipoise. 9.The composition of claim 8 wherein the bait base comprises feedingstimulants.
 10. The composition of claim 9 , wherein the bait basefurther comprises one or more gelling agent(s).
 11. The composition ofclaim 10 wherein the gelling agent(s) comprises about 0.1 to 5 wt-% ofthe bait base.
 12. The composition of claim 8 wherein the insecticide isacephate or methamidophos.
 13. The composition of claim 8 wherein thebait base comprises up to 50 wt-% of borax or boric acid.
 14. Thecomposition of claim 8 comprising: (a) about 1 wt-% acephate; (b) about30 wt-% water; and (c) the balance being a bait base comprising feedingstimulants and a gelling agent.
 15. The composition of claim 14 whereinthe gelling agent is a modified starch in an amount of about 1 wt-% ofthe total weight of the bait base.
 16. The composition of claim 15having a viscosity of about 180,000 centipoise.
 17. A method ofcontrolling insect pests comprising applying to areas to be controlledan effective amount of a composition according to claim 8 .
 18. Themethod of claim 17 wherein the insect pests are cockroaches.
 19. Themethod of claim 16 wherein the composition is applied to cracks andcrevices in commercial establishments.
 20. A method of controllingcockroaches comprising applying to areas to be controlled an effectiveamount of a composition according to claim 14 .
 21. A kit for thepreparation and application of an insecticidal bait compositioncomprising: (a) a closed impermeable container having a water-sensitiveinsecticide in pellet or powder form therein; and (b) a closed packetcomprising a base bait.
 22. The kit of claim 21 , which furthercomprises a dispensing container.
 23. The kit according to claim 22wherein the dispensing container is a syringe, cartridge or cylinder.24. The kit according to claim 22 wherein the dispensing container isused in conjunction with a bait applicator.
 25. The kit according toclaim 21 wherein the closed impermeable container is a glass vial. 26.The kit according to claim 21 wherein the closed packet is a resealableplastic bag.